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Metronidazole resistence in clinical cases of giardiasis.
Perglerová, Aneta ; Tůmová, Pavla (advisor) ; Uzlíková, Magdalena (referee)
Metronidazole (MTZ) targets a spectrum of anaerobic pathogens ranging from bacteria to eukaryotic parasites, including the protist Giardia intestinalis (Metamonada). Despite the long time and widespread use of MTZ, understanding giardiasis treatment failure (G-TF) is incomplete. Most of the knowledge was gained on laboratory-generated resistant lines or on clinical lines without data on the treatment outcome. In cooperation with Bulovka University Hospital in Prague, 70 giardiasis cases were followed between 2020-2023, of which 25.7% exhibited the G-TF. Giardia genotyping revealed that G-TF cases belonged to the same genetic group (assemblage B, mainly BIII); and G-TF cases were all imported, out of which 60% were from returning travellers from India. To test the hypothesis that resistance is genetically determined/associated with a transmissible genotype, genetic polymorphisms shared in Giardia G-TF samples in a set of genes involved in MTZ metabolism and detoxifications (NR1, NR2, prx1, hmp) were examined. The analysis revealed amino acid substitutions (K42E, K139R) in NR2 isolates of G-TF patients, which might affect protein structure. Also, a gene dosage effect as drug resistance co-variant/cause due to gene duplications or deletions of the hmp gene was tested. Results from dPCR revealed that...
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